1. Field of the Invention
The present invention relates to a method of processing a silver halide photosensitive material.
2. Description of the Related Art
In recent years, various line-ups of photo-sensitive materials ranging from low speeds to high speeds are provided. For example, with respect to photosensitive materials for photographing, there are those of speed indication ranging from about ISO 25 to ISO 3200. Those of low speed need a high intensity of light and thus are not suitable for snap photographing performed at a high shutter speed, but photographed images are smooth and coarse grains are not pronounced (being excellent in graininess). On the other hand, those of high speed enable photographing without flashlights and thus widen the range of photographing objects, but the graininess of photographed images is conspicuous (being poor in graininess). From an idealistic viewpoint, a high-speed photosensitive material exhibiting excellent graininess is demanded. The cause of the coarse grains of images is the large size of silver halide emulsion grains as a photo-sensitive element and as a responsibility to display elements. Consequently, minimizing the grain size is needed for attaining an enhanced graininess. However, reducing the grain size would cause a speed drop. Thus, a speed increase technology for compensating for the speed drop is required separately. A variety of methods are being employed for increasing the inherent sensitivity of silver halides. For example, a speed increase by a chemical sensitizer such as sulfur, gold or a compound of Group VIII metal, a speed increase by the use of a chemical sensitizer such as sulfur, gold or a compound of Group VIII metal in combination with an additive capable of promoting the sensitizing effect of the chemical sensitizer and a speed increase by the addition of an additive capable of exerting a sensitizing effect depending on the type of silver halide emulsion are being performed. Furthermore, a method of speed increase wherein a so-called reduction sensitizer is added to thereby form reduced silver in the internal part of emulsion or on the surface thereof is well known.
Sensitizing technologies wherein an organic electron-donating compound comprising an electron donating group and a split-off group is employed are reported in the specifications of some patents and the like (for example, U.S. Pat. Nos. 5,747,235, 5,747,236 and 6,054,260; EP No. 786,692A1; EP's 893,731A1 and 893,732A1; and WO 99/05570).
However, when the above organic electron-donating compound was used in the development processing after imagewise exposure in which a processing step by a developer inducing a solution physical development was included, there occurred such a problem that although an effect could be recognized, the degree of speed increase was low and the storability was deteriorated, as compared with those attained in the conventional speed increase method wherein reduction sensitizers were added.
It is reported in Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-) 2001-42466 that a storability enhancement can be achieved by the use of an organic electron-donating compound in combination with a specified storage improver. However, results of a follow-up test showed that the effect of storability enhancement was trivial in the development processing step wherein the solution physical development occurred.